Many newcomers to the field of UV photography are intimidated by the cost of dedicated UV lenses. No wonder as these easily run to several thousand dollars.
Finding the more affordable alternative might not always be easy as there are many pitfalls on the road from getting a candidate lens to putting it into successful service for UV work. Again, price is a first stumble block, secondly, getting the lens to work on your camera of choice is another.
The Petri line-up of lenses dates from early '60s and here you can find good candidates for UV. They fetch fairly low prices on the second-hand market and there is little interest from collectors, so time is now to pick up some of them. These lenses have Petri breech-lock mount, which isn't compatible with anything except Petri's own cameras. The mount does not lend itself to rapid swapping of lenses which probably explains why its popularity faded away. However, it does secure a sturdy connection to the camera and is not prone to wear. The Petri system have a quite short register (distance from mount to film plane) and the internal working of these lenses makes modifying the mount into something else difficult. If infinity focus is to be attained you have to put the lens on some mirrorless camera.
The outward appearance of the Petri lenses is typical for their period. They look nice and most have scalloped chrome focusing rings. The longer lenses are an exception and are finished in satin black instead. The internal construction is pretty basic, however a clean sample treated with care should last a life time.
You can find these lenses under the Petri label, or designated Kuribayashi, Kyoei, W.Acall, and probably more. As long as they have the breech-lock mount and have simple coatings they should be fine for UV applications. Don't expect UV-Nikkor performance at a fraction of the cost, though! All of them should be stopped down a bit to deliver best UV results. Flare can be a problem due to the pretty basic coatings, so ensure the front of the lens is well shaded.
Petri lenses tested for UV are as follows;
- 35 mm f/3.5 (doubt the f/2.8 is good but not tested). Does very well in UV. 46 mm threads.
- 55 mm f/1.8 (not great for UV as expected from its high speed, but you can get interesting pictures from it. Probably only goes to just below 380 nm). 55 mm threads.
- 135 mm f/3.5 (not tested the f/2.8). A good all-round UV performer. 52 mm threads.
- 200 mm f/4 (not tested the faster f/3.5). A good all-round UV performer. 55 mm threads. Stop down to f/11 or beyond for best results.
- 400 mm f/6.3. Must be stopped down preferably beyond f/11, but results can be surprisingly good. 72 mm filter threads so using a rear-mounted filter or filter box is recommended. It has an excellent tripod mount as well and is very light weight for its focal length. I modified my 400 to be F-mount only.
The 300 mm f/5.5 is currently on its way so has not been tested yet. However, its design is pretty much the same as the 400 so my guess is they will have similar UV behaviour. This lens, like the 400 brother, will be converted to F-mount.
These lenses go for very low prices and you can easily pick up clean samples for well under $50. In fact I recently have purchased 35/3.5, 55/1.8 and 135/3.5 in the area of $15 each. The longer lenses tend to cost a little more, probably because they usually are sold with a case so makes shipping more expensive. Still $ 55 sufficed a few weeks ago to obtain a mint copy of the 200/4 Petri.
Now, to the more nitty-gritty part of the affair. You have the lens(es) and want to use them on your camera(s). To retain infinity focus, using an adapter on a mirrorless camera is the only viable option. A possible exception being the 300 & 400 lenses, but they do need substantial modification to retain infinity focus say with an F mount.I managed to track down a few Petri-m43 adapters, but they are very scarce. Adapters for Petri to other systems such as Sony or Fuji are still available, though. An easier approach is getting a Petri 2X TC (approx. $15) or a Petri extension tube set (again about $20), plus a Minolta MD to m4/3 (or your mirrorless system) adapter. Remove the mount on the MD adapter and replace it with the female mount from the TC. Register distance difference between MD and Petri is a fraction of a mm so you are more or less done to infinity when the lens is stopped down.
Many UV shooters do close-ups so you actually would need to add extension to your lens anyway and keeping infinity focus is not that important. In this case, you can combine the female part of a Petri extension tube to an M42 adapter for your camera and you're done. Alternatively, if you have a spare Petri 2X TC, remove the male Petri mount at its end and put a bayonet mount for your system there.The internals of the TC can go into a UV-capable teleconverter for your system.
Here are some examples of components to fit the 135 mm f/3.5 Petri lens.
First, an overview, showing the lens itself and all the auxiliary components. Top row left to right is Petri extension tube set, modified MD-m4/3 adapter with Petri female mount. Bottom left to right is a Petri-m4/3 adapter (modified to have a tripod mount), the Petri 135 itself, and finally, the remnants of a Petri 2X TC (optics used to make a UV TC for the UV-Nikkor) with a Nikon F mount added to its rear. A CPU is installed of course.
NG_Petri135DSC_2650.jpg 460.93KB 2 downloads
Then, a detail of the combination of Petri female mount in front, from the extension tube kit, with an M42-F adapter in the rear. Again a CPU is installed as the combination is to be used on my F cameras.
NG_Petri135DSC_2655.jpg 422.66KB 1 downloads
To underscore, now is the time to get these cheap lenses for UV. If interest in them increases so will the price level.